“When titans clash … no one wins.” Conan O’Brien and his TBS late-night show are back at Comic-Con in San Diego for a second consecutive year, airing from the Spreckles Theatre. Wednesday’s night first Conan of the SDCC season opened with the host and his longtime sidekick Andy Richter squaring off in a Batman v Superman homage/takedown. After taking in a screening of X-Men vs. The Avengers — down, fanboys, down! — they brawl over a spat so trivial, they soon forget what it was.